The subject matter herein relates generally to battery modules.
Battery modules, such as those for electric vehicles or hybrid vehicles, typically includes a plurality of cells grouped together to form the battery modules. The battery modules are connected together with a cover assembly to form battery packs. Each of the cells includes positive and negative cell terminals that are electrically connected together via the cover assembly. Different types of battery modules are formed using different types of cells. For example, one type of battery modules are known as pouch type battery modules, another type of battery modules are known as prismatic battery modules, and a third type of battery modules are known as cylindrical battery modules. Prismatic battery modules use prismatic battery cells that are stacked together. The positive and negative cell terminals are connected using bus bars.
Known battery packs typically include electrical components that are configured to monitor the voltage and other characteristics of each of the cells of each of the battery modules. For example, the battery pack may include a central controller that is electrically connected to each bus bar by cables, wires, wire harnesses, electrical connectors, and the like. In some known battery packs, an electrical conductor of a wire or cable leading to the central controller is directly electrically connected to a corresponding bus bar by soldering, laser welding, or another joining process. But, it may be difficult to provide a reliable electrical connection at the joint using such joining processes because the conductors and the bus bars may be formed of different conductive materials that do not readily join together. For example, the conductors may be copper and the bus bars may be aluminum, and soldering or welding the copper to the aluminum may produce a brittle intermetallic layer at the interface, resulting in a brittle joint. The brittle joint may risk premature breaking, requiring additional maintenance. Furthermore, in at least some known battery packs, the cables or wires are only secured to an assembly that holds the bus bars via the joints formed by soldering or welding the conductors to the bus bars. Thus, the electrical connection points are also the mechanical connection points. Stresses, strains, vibrations, and other forces on the cable or wire are transferred to the joints, which risks damaging the joints and breaking the electrical connection to the bus bars, especially if the joints are already brittle, as described above.
A need remains for improving the reliability of the electrical connections between the bus bars and the conductors of the cable or wire. A need remains for providing strain relief to the cable or wire to reduce forces on the electrical connection joints.